In doing a translation on duolingo, another translator had translated a phrase to say "at the service of X". I edited this to "in the service of X" and left a comment that as a native speaker, hearing ...

I found the word, “at turns” in the beginning sentence of the article of Time magazine (September 18) titled, “How Mitt Romney’s Luck Ran Out” that reads:
“For a good long while, Mitt Romney was the ...

What’s the difference between “to be in use” and “to be at use”?
I have impression that former states that something is being used, while the latter means something proves to be useful — the same as ...

What is the difference between 'to my face', 'at my face' and 'in my face'? I searched it on google books and got results for all of them with various hits. Does one seem more accurate over the other? ...

What is the difference between at a hotel and in a hotel? The NYTimes seems to be using both of them. I looked up the ngram on google and it seems in a hotel is used more often than at a hotel, which ...